To be familiar with SQL Server on Linux, please read the following article I have recently written, this is about how to install and connect to SQL Server on Linux Ubuntu
Install and connect to SQL Server vNext on Linux Ubuntu - Part 1
Install and connect to SQL Server vNext on Linux Ubuntu - Part 2
SQLDBDiff 6.0 current build is supporting SQL Server on Linux (vNext), in SQLDBDiff tool you will connect to SQL Server vNext as the same way you connect to SQL Server on-premises, you only need to enter the IP Adr and SQL login for your SQL instance on Linux